3-d flight table



NOV. 24, 1964 c, EDWARDS ETAL 3,158,018

3-D FLIGHT TABLE 2 Sheets-Sheet 1 Filed May 13, 1958 IN YE N TORS cmmuss M. znwmws MURRAY KANEs PAUL. E FISCHER. FRANKLIN O. GEIGER MELVIN S. FEDER JOHN R. FARRON HT RNEYS Nov. 24, 1964 c, EDWARDS ETAL 3,158,018

3-D FLIGHT TABLE 2 Sheets-Sheet 2 Filed May 13, 1958 HT OED/5.78

MWBDREOO A United States Patent Office 3,158,018 Patented Nov. 24, 1964 3-D FLIGHT TABLE (Iharles M. Edwards, Royal Oak, and Murray Kanes, Birmingham, Mich, Paul F. Fischer, Fullerton, Gaiifl, Franklin 0. Geiger, Livonia, Mich, Melvin S. Feder, Bethpage, N.Y., and John R. Farron, Gal; Park, Mich, assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed May 13, 1958, Ser. No. 735,076 4 Claims. (Cl. 73-1) This invention relates generally to flight tables and more specifically to flight tables capable of use in simulating and testing aeronautical equipment.

In the prior art, flight tables have been generally of standard design wherein minor improvements in construction have produced minor improvements in performance. These prior art flight tables have, in addition, been greatly lacking in versatility. The instant invention overcomes all of the attendant disadvantages by being completely new in design, thus realizing greater performance and versatility. In addition, the instant invention is relatively simple to construct and maintain.

A principal object of the invention is to provide a high performance flight table.

Another object of the invention is to provide a versatile flight table.

Still another is to provide a new concept of flight table construction.

Yet another object is to provide a new flight simulator.

Still another object is to provide a new testing device.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view in perspective of the flight table and FIG. 2 is a functional block diagram showing the flight table in a typical mode of operation and shows the preferred form of servo to be used with the flight table.

FIG. 3 is a section through the outer gimbal showing the construction of that gimbal.

Referring to FIGURES 1 and 3, the flight table is supported on base 12. Base 12 in its preferred form is a heavy, massive structure which tends to minimize transmission of table vibrations to ground. Casters (not shown) are mounted on the base 12 to provide mobility. During operation of the flight table, the unit is elevated on four machine jacks (not shown) so that the weight of the system is removed from the casters. Mounted on the base 12 are massive supports 14 which serve as trunnions. Supports 14 have rotatably fixed thereto at 16 and 18 the pitch gimbal 20. The pitch gimbal 20 which is the outer gimbal of the flight table 10 rotates about an axis designated as the y axis. In shape, the pitch gimbal 20 is ellipsoidal and is provided with cutouts 22 which allow access to elements contained within the pitch gimbal 2t). structurally the pitch gimbal comprises two thin metal shells 21 separated by a bonded plastic foam core 23.

A thin aluminum alloy casting in the shape of a cylindrical bucket constitutes the yaw gimbal 24. Yaw gimbal 24 which is the middle gimbal has fixed thereto shaft 26 which is rotatably contained within the pitch gimbal 20 at 28. Yaw gimbal 24 rotates about an axis designated as the z axis.

Rotatably mounted on the yaw gimbal 24 is an annular spur gear 30 which constitutes the roll, or inner gimbal. The gear 30 is fully described in copending application Serial Number 736,939, filed May 21, 1958. Roll gimbal 30 rotates about an axis designated as the x axis. Fixed to the perimeter of the gimbal 30 are mounting bolts 31. Mounting bolts 31 are used to mount components under test to the table 10.

Gears 34 and 36 are mounted on opposing ends of the elliptical gimbal 20. Meshing gear 38, which is driven by motor 40, meshes with gear 34 to rotate gear 34 and gimbal 20. Rotation of gimbal 20 and the operation of motor 40 will be explained in greater detail later. A pitch axis tachometer 42 is driven by meshing gear 38 and operates to measure the rate of pitch gimbal rotation. Gear 44 is a meshing gear which meshes with gear 36 and instrument gear 46. Rotation of gear 46 rotates instrument shaft 48 and the movements of the pitch instrumens 50.

Mounted on the pitch gimbal 20 is the yaw drive motor 51 which drives gears (not shown) mounted on shaft 26. Also mounted on the pitch gimbal 20 are the yaw instruments 52 which are activated by rotation of shaft 26. A yaw tachometer of conventional design (not visible) is fixed to the yaw gimbal and is driven by the rotation of shaft 26. The yaw tachometer thus measures the rate of yawing.

A roll drive motor 54 is mounted on the yaw gimbal 24. The gear 56, which is coupled to the shaft of motor 54 through an opening in the support 58, is rotated by motor 54. The gear 56 meshes with the roll gimbal 30 and drives the gimbal when the motor 54 is activated. This operation will be described in greater detail subsequently. Mounted co-axially on the gear 56 is the gear 60. A tachometer 62 having a shaft 64 has a gear 66 mounted on the shaft 64. The gears 60 and 66 mesh to translate rotational motion produced by the motor 54 to the tachometer 62. The tachometer 62 is thus able to measure the rate of roll gimbal rotation Coupled to and driven by the roll gimbal 30 when it rotates is gear 61. Gear 61 is mounted on a shaft (not shown) which operates to drive the roll instruments 63.

An electrical terminal box 70 is mounted on the support 14- and feeds electrical energy to the electrical slip rings 72 and those elements of the system requiring electrical power. Mounted on the opposing support 14 are hydraulic slip rings 74 which supply fluid to the hydraulic motors 40, 51 and 54.

The operation of the motors can be best understood by referring to FIG. 2. Inasmuch as all gimbals operate in the same manner, only the pitch gambal operation will be described, it being understood that similar operation is provided by the yaw and roll gimbals. An analog computer 76 is coupled to the pitch servo loops 78. The output from the computer, which is an A.C. analog voltage of pitch gimbal rotation, is fed to a summing circuit 80. An amplifier-demodulator-filter 82 is coupled to and receives the output from the summing circuit and converts the A.C. analog into a DC. analog. The spool of the flow valve 84 is operated by the output of the amplifier-demodulator-filter which is fed through a compensating circuit 86. Flow valve 84 is coupled to the hydraulic pitch motor 40 and operates to rotate the motor shaft an amount dictated by the valve of the output from the computer 76. The output from motor 40 is then coupled to the pitch axis tachometer 42 which is further coupled to the summing circuit 80. Operation of the tachometer 42 results in a rate feedback to the summing circuit 80 to null out the error signal which is generated to rotate the pitch gimbal. Also coupled to and driven by the motor 46 is the pitch gimbal 26). As the pitch gimbal is rotated by the output from motor 40, the pitch gimbal instruments 50 are activated. Gimbal instruments 50 are high precision resolvers and otentiometers whose outputs may be used in various ways. FIG. 2 shows one way in which the instruments may be used. The outputs from the instruments 50 are fed back to the computer 76 to null out the input to the gimbal servo 78. This arrangement of elements is one in which the system may be used in the simulation of an automatic pilot.

If preferred, the gimbal instruments 50 may be coupled to a recording instrument to record such parameters as gimbal rotation; rate of rotation and acceleration. A further preference might be to use the table as a test instrument. In this case components to be tested are mounted on the roll gimbal 30 by means of the mounting bolts 31 and the table is made to gyrate in accordance with output data from the computer 76. Thus, components to be tested are made to behave as they would in an actual flight: the output from the component being coupled either into the computer 76 or a recording device.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. A flight table comprising a supporting base, a first gimbal pivotably mounted on said base, wherein said first gimbalcomprises two thin metal shells separated by a plastic foam core, a second girnbal pivotably mounted on said first gimbal rotatable in a plane which is orthogonal to the plane in which said first gimbal rotates, electro- 25 hydraulic servo means geared to said gimbals whereby said gimbals are responsive to said electro-hydraulic servo means.

2. The structure of claim 1 wherein said first gimbal is hollow and contains a compressible substance.

3. The structure of claim 1 wherein said first gimbal comprises two thin metal sheets separated by a plastic foam core and said base is massive compared to other components of the structure.

4. The structure of claim 3 wherein rotatably mounted on said second gimbal is a gear, including mounting means fixed to said gear, said mounting means .being adapted to mount components under test on said flight table.

References Cited in the file of this patent UNITED STATES PATENTS 1,253,666 Carrie Jan. 16, 1918 2,046,890 Young July 7, 1936 2,559,577 Tear July 3, 1951 2,700,888 Good et a1 Feb. 1, 1955 2,761,306 McNutt Sept. 4, 1956 2,902,772 Ciscel Sept. 8, 1959 2,940,176 Jessup June 14, 1960 FOREIGN PATENTS 160,316 Great Britain Mar. 24, 1921 

1. A FLIGHT TABLE COMPRISING A SUPPORTING BASE, A FIRST GIMBAL PIVOTABLY MOUNTED ON SAID BASE, WHEREIN SAID FIRST GIMBAL COMPRISES TWO THIN METAL SHELLS SEPARATED BY A PLASTIC FOAM CORE, A SECOND GIMBAL PIVOTABLY MOUNTED ON SAID FIRST GIMBAL ROTATABLE IN A PLANE WHICH IS ORTHOGONAL TO THE PLANE IN WHICH SAID FIRST GIMBAL ROTATES, ELECTROHYDRAULIC SERVO MEANS GEARED TO SAID GIMBALS WHEREBY SAID GIMBALS ARE RESPONSIVE TO SAID ELECTRO-HYDRAULIC SERVO MEANS. 